The invention pertains to electrical apparatuses, termite sensing apparatuses, and methods of forming electrical apparatuses.
A prior art apparatus and method for detecting termite infestation is described with reference to FIGS. 1 and 2. Specifically, a termite detection device 10 is shown in an assembled configuration and inserted within the ground 12 in FIG. 1, and is shown in a disassembled configuration in FIG. 2. Device 10 comprises an outer receptacle 14 having a plurality of orifices 16 (only some of which are labeled) extending therethrough. A cap (or a lid) 18 is provided to cover the top of receptacle 14. Preferably, receptacle 14 is inserted into the ground to a depth at which cap 18 will rest approximately at a surface of the ground.
A pair of wooden blocks 20 and 22 are provided within receptacle 14, and constitute xe2x80x9cbaitxe2x80x9d for termites proximate to device 10. A holder 24 is provided between blocks of wood 20 and 22 and comprises a shelf 26 upon which blocks 20 and 22 rest. Holder 24 and blocks 20 and 22 together comprise an assembly 27 which can be removably inserted into receptacle 14.
Holder 24 comprises a portion 28 which protrudes upwardly beyond blocks 20 and 22 in the assembled configuration of FIG. 1. Portion 28 comprises an eye 30 (shown in FIG. 2) which can simplify removal of assembly 27 from receptacle 14 using a tool with a hook.
In operation, receptacle 14 is inserted into ground 12, and blocks 20 and 22 are subsequently left in receptacle 14 for a period of time. Blocks 20 and 22 function as a sensing apparatus to determine if a termite infestation is present in an area proximate device 10. Specifically, if termites are present, such will penetrate through orifice 16 to reach wooden blocks 20 and 22. The termites will then burrow into the wooden blocks 20 and 22.
At regular intervals, cap 18 is removed and blocks 20 and 22 withdrawn from device 14. Blocks 20 and 22 are then surveyed for termite-inflicted damage, and possibly a presence of termites themselves.
Generally, a number of apparatuses 10 will be spread around a given location, such as, for example, a house or other wooden structure. Each of the apparatuses will be checked at a regular interval to determine if a termite infestation is occurring proximate the structure. Also, each of the devices will be mapped relative to one another, and relative to the structure. A comparison of the amount of termite-inflicted damage occurring at the respective devices 10 can then enable a person to determine an approximate localized region of any occurring termite infestation. It can be advantageous to pinpoint a localized region of infestation as such can limit an amount of pesticide utilized for destroying the termites.
Difficulties can occur in monitoring the amount of termite-inflicted damage occurring at each of the many devices 10 provided around a structure. For instance, it can be difficult to regularly and accurately document the amount of damage at each of the devices. As an example, it can be difficult to remember exactly which of the various devices correlates to a specific location on a map of the devices. As another example, it can be difficult to accurately record a reading of termite-inflicted damage associated with an individual device. As yet another example, it can be tedious and time-consuming to open all of the receptacles 14 proximate the given structure and manually check the blocks 20 and 22 within the receptacles for termite-inflicted damage.
One method of reducing the above-discussed difficulties is to provide bar codes on the lids 18 of receptacles 14. Such bar codes can be scanned to specifically identify a particular device which can simplify correlating the devices to locations on a map of the devices. However, ascertaining an amount of termite-inflicted damage can still be time-consuming in that the receptacles still have to be opened and the blocks of wood manually checked to determine if termite-inflicted damage has occurred to the wood.
A recently proposed improvement for monitoring an amount of termite-inflicted damage in a device similar to device 10 is described with reference to FIGS. 3 and 4. Referring to FIG. 3, a device 100 comprises a receptacle 14 of the type described above with reference to FIG. 1, and comprises a cap 18 configured to be received over an open type of receptacle 14. Device 100 further comprises the pair of wooden blocks 20 and 22, and a holder 110 similar to the holder 24 described above with reference to FIG. 1. Holder 110 can comprise, for example, plastic, and differs from holder 24 in that it comprises both a top shelf 112 and a bottom shelf 114, whereas holder 24 only comprised a bottom shelf. In the shown embodiment, shelf 112 is configured with a slit 116 so that shelf 112 can be slid over a prior holding device (such as the device 24 of FIG. 1) to form the holding device 110. Slit 116 is optional, and shelf 112 can be molded in one piece with the other components of holder 110. Holder 110 can be considered as comprising a pillar 111 extending between shelves 112 and 114, and an extension 113 protruding above shelf 112. Extension 113 is configured to enable a person to lift holder 110 by the extension, and in the shown embodiment comprises an eye 115 extending therethrough. Shelf 112 can comprise an electrically insulative material, such as, for example, plastic (for instance, polypropylene).
Device 100 further comprises an electronic termite sensing loop 118 of conductive material. Loop 118 is formed on a substantially planar substrate 120, and is preferably formed of material which can be removed by termites. Exemplary materials are printable materials comprising conductive particles, such as, for example, metal particles or carbon particles. Suitable materials are, for example, silver-filled printed thick film ink and silver-filled epoxy. An exemplary silver-filled ink is Dupont Electronics 5028(trademark) (available from Dupont Electronics of Wilmington, Del.), which is a silver polymer conductor. Another suitable material for loop 118 is a carbon-particle-containing ink (typically the particles will consist essentially of carbon), such as, for example, a material marked by Dupont Electronics as 7102(trademark) Carbon Polymer Conductor (available from Dupont Electronics of Wilmington, Delaware). Carbon-particle-containing inks can be cheaper than other inks, better accepted by pests (i.e., apparently more palatable to the pests), and less subject to environmental damage. Further, the inclusion of carbon inks in a circuit can lower an electrical conductivity (i.e., raise a resistivity) of the circuit. The lowered conductivity can increase the reliability of data obtained from the circuit. More specifically, the inclusion of carbon-particle-containing inks in loop 118 can render the circuit of loop 118 less susceptible to registering false negative readings if mud or water bridges an opening in the circuit.
Substrate 120 is preferably formed of material which can be removed by termites. Exemplary materials are polyethylene foam and polyester. The conductive material of loop 118 can be directly applied to substrate 120 using, for example, screen printing methods. Substrate 120 can be pretreated prior to applying the conductive material of loop 118 over substrate 120. Such pretreatment can comprise, for example, flame pretreatment to promote adhesion of the conductive material to the foam.
An electrically insulative protective material 127 (only some of which is shown in FIG. 3) is provided over loop 118 and substrate 120. Protective material 127 can protect conductive loop 118 from water, abrasion or other environmental damage. the insulative protective material can comprise, for example, a resin which is provided as a liquid and cured by exposure to one or more of heat, ultraviolet light and oxygen. A suitable insulative protective material is a material selected from the general class of epoxy resins (such as, for example, a two-part epoxy resin). Another suitable insulative protective material is a material selected for the general class of thick film inks. Exemplary insulative protective materials are Dupont 5015(trademark) and 5018(trademark) (available from Dupont Electronics of Wilmington, Del.), with 5018(trademark) being an ultraviolet light curable dielectric material. Another exemplary insulative protective material is a tape adhered over loop 118 with an adhesive.
A termite attractant (such as, for example, a suitable pheromone) can be provided in addition to the insulative protective material. Such attractant can, for example, be formed over the insulative protective material or blended within the insulative protective material.
In the shown configuration, substrate 120 comprises a pair of opposing sidewall edges 121 and 123, and a plurality of notches 122 extending into sidewall edges 121 and 123. Notches 122 are provided to form crevices within which the termites can burrow.
Conductive loop 118 comprises a pair of ends (130 and 132), with end 132 connected to a first prong 134 and end 130 connected to a second prong 136. Device 100 further comprises a circuit board 150 having circuitry (not shown in FIG. 3) supported thereby and a pair of orifices (152 and 154) extending therethrough. Board 150 can be considered as a circuit support. Shelf 112 has a pair of orifices 156 and 158 extending therethrough, and configured to be aligned with orifices 152 and 154 of circuit board 150. In operation, device 100 is assembled by providing substrate 120 within holder 114 such that prongs 134 and 136 extend through orifices 156, 158, 152 and 154 to retain circuit board 150 atop shelf 112. Circuit board 150 can then be adhered to shelf 112 and/or prongs 134 and 136. Blocks 20 and 22 are subsequently provided within holder 110 to form an assembly 160 which can be removably inserted within receptacle 14.
The circuitry supported by circuit board 150 can comprise at least a portion of a transponder unit and is configured to be incorporated into a passive radio frequency identification device (RFID) system. The transponder unit can comprise, for example, a parallel resonant LC circuit, with such circuit being resonant at a carrier frequency of an interrogator. The transponder unit is in electrical connection with an antenna 155 provided externally of the circuitry supported by board 150. Exemplary circuit board/transponder unit assemblies are described in U.S. patent application Ser. No. 08/705,043, filed Aug. 29, 1996, which is assigned to the assignee of the present invention and hereby incorporated by reference.
Referring to FIG. 4, an RFID system 60 comprises the transponder supported by a structure 150 (which can comprise, for example, a circuit board) and an interrogator 45 configured to be passed over such transponder unit. Interrogator 45 comprises a coil antenna configured to stimulate the transponder unit. Such coil antenna consists of one or more coils of conductive material provided within a single plane, and can be in the form of, for example, a loop antenna.
In operation, interrogator 45 provides a carrier signal which powers (stimulates) the transponder unit supported by board 150 and causes a signal to be transmitted from the transponder unit. The signal comprises data which identifies the transponder unit. Such signal can also identify if the conductive loop 118 is broken. The signal is received by interrogator 45, and eventually provided to a processing system configured to decode and interpret the data. Such processing system can be provided in a portable unit with interrogator 45, or can be provided in a separate unit to which data from interrogator 45 is subsequently downloaded.
By having a signal from the transponder unit change with a break in circuit 118, device 100 can indicate if damage has occurred to loop 118 through a signal sent to an interrogator. Such can enable persons utilizing the device to ascertain if termites are present without having to remove blocks 20 and 22 from receptacle 14, and even without having to remove the lid 18 from receptacle 14. Once damage to circuit 118 is detected with an interrogator, persons can remove assembly 160 and quantitate an amount of damage occurring within blocks 20 and 22 to determine an extent of termite infestation.
The device 160 is suitable for many applications in which it is desired to detect termite infestation. However, the device can be difficult to assemble and utilize in particular applications. Accordingly, it would be desirable to develop alternative devices for detecting termite infestation.
In one aspect, the invention encompasses an electrical apparatus. Such apparatus comprises a first substrate having first circuitry thereon. The first circuitry has a terminal extending therefrom, and the terminal defines a first electrical node. The apparatus further comprises a first dielectric material covering a predominate portion of the first circuitry and not covering the first electrical node. Additionally, the apparatus comprises a second substrate having second circuitry thereon. The second circuitry has a terminal extending therefrom, and such terminal defines a second electrical node. A second dielectric material covers a predominate portion of the second circuitry, but does not cover the second electrical node. The second substrate comprises a different material than the first substrate. A portion of the second substrate is over a portion of the first substrate to define an overlap between the first and second substrates. The second electrical node overlaps the first electrical node in the overlap between the first and second substrates. A conductive material is within the overlap between the first and second substrates and electrically bonds the first and second electrical nodes to one another.
In another aspect, the invention encompasses a termite sensing apparatus. Such apparatus comprises a first substrate having a conductive loop thereon. The loop has a pair of terminals extending therefrom, with the terminals defining first and second electrical nodes. A first dielectric material covers a predominate portion of the conductive loop and defines a fluid-type protective layer over such predominate portion of the conductive loop. The first dielectric material does not cover the first and second electrical nodes. The termite sensing apparatus further comprises a second substrate having a pair of conductive lines thereon. The conductive lines are a first line and a second line, and are spaced from one another. The first conductive line has a pair of opposing ends, and the second conductive line has a pair of opposing ends. One of the opposing ends of the first conductive line defines a third electrical node, and the other of the opposing ends of the first conductive line defines a fourth electrical node. One of the opposing ends of the second conductive line defines a fifth electrical node, and the other of the opposing ends of the second conductive line defines a sixth electrical node. The third and fifth electrical nodes are proximate one another. A portion of the second substrate is over a portion of the first substrate to define an overlap between the first and second substrates. The third electrical node overlaps the first electrical node in the overlap between the first and second substrates, and the fifth electrical node overlaps the second electrical node in such overlap between the first and second substrates. A conductive material is within the overlap between the first and second substrates. Such conductive material electrically bonds the first and third electrical nodes to one another, and electrically bonds the second and fifth electrical nodes to one another.
In yet other aspects, the invention encompasses methods of forming electrical apparatuses.